I haven't had that issue myself on my own mod map. My best guess would be the mod map you've tried adding them too has been setup slightly different to the default way.
Or it could be you made a mistake when adding the crops to that mod map, which is very easy to do.
The issue is the distance textures are not rendering ingame. Make sure those have been copied over to the mod correctly, and make sure that the "oat.xml" has been updated with my custom one. (Sometimes when copying files from one folder to another in windows it doesn't always copy everything across.)
Are you trying to use an existing (old) savegame with the new textures? If so this cause the issue as well.